[{"id":3681554,"web_url":"http://patchwork.ozlabs.org/comment/3681554/","msgid":"<362cafcd-2ce0-4da0-be6b-39a78c6b94b7@suse.de>","list_archive_url":null,"date":"2026-04-23T16:06:54","subject":"Re: [PATCH nft] evaluate: zap useless 0-shifts","submitter":{"id":90904,"url":"http://patchwork.ozlabs.org/api/people/90904/","name":"Fernando Fernandez Mancera","email":"fmancera@suse.de"},"content":"On 4/22/26 7:26 PM, Florian Westphal wrote:\n> There is a (not yet applied) kernel patch that rejects 0-shifts,\n> auto-suppress them at eval stage.\n> \n> Signed-off-by: Florian Westphal \n> ---\n\nReviewed-by: Fernando Fernandez Mancera \n\nThat is quite elegant indeed, thanks!\n\n> src/evaluate.c | 6 ++++++\n> 1 file changed, 6 insertions(+)\n> \n> diff --git a/src/evaluate.c b/src/evaluate.c\n> index 482708ae6191..8bb7b6095309 100644\n> --- a/src/evaluate.c\n> +++ b/src/evaluate.c\n> @@ -1454,6 +1454,12 @@ static int expr_evaluate_shift(struct eval_ctx *ctx, struct expr **expr)\n> \t\t\t\t\t \"shifts exceeding %u bits are not supported\", UINT_MAX);\n> \n> \tshift = mpz_get_uint32(right->value);\n> +\tif (shift == 0) {\n> +\t\t*expr = expr_get(left);\n> +\t\texpr_free(op);\n> +\t\treturn 0;\n> +\t}\n> +\n> \tif (ctx->stmt_len > left->len)\n> \t\tmax_shift_len = ctx->stmt_len;\n> \telse","headers":{"Return-Path":"\n ","X-Original-To":["incoming@patchwork.ozlabs.org","netfilter-devel@vger.kernel.org"],"Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (1024-bit key;\n unprotected) header.d=suse.de header.i=@suse.de header.a=rsa-sha256\n header.s=susede2_rsa header.b=XSuNTkmJ;\n\tdkim=pass header.d=suse.de header.i=@suse.de header.a=ed25519-sha256\n header.s=susede2_ed25519 header.b=6vQ0TrNQ;\n\tdkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de\n header.a=rsa-sha256 header.s=susede2_rsa header.b=XSuNTkmJ;\n\tdkim=neutral header.d=suse.de header.i=@suse.de header.a=ed25519-sha256\n header.s=susede2_ed25519 header.b=6vQ0TrNQ;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=172.105.105.114; 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